mL Of Wastewater Research Articles

Sequential electrochemical treatment of dairy wastewater using aluminum and DSA-type anodes

Dairy wastewater is characterized by a high content of hardly biodegradable dissolved, colloidal, and suspended organic matter. This work firstly investigates the performance of two individual electrochemical treatments, namely electrocoagulation (EC) and electro-oxidation (EO), in order to finally assess the mineralization ability of a sequential EC/EO process. EC with an Al anode was employed as a primary pretreatment for the conditioning of 800 mL of wastewater. A complete reduction of turbidity, as well as 90 and 81% of chemical oxygen demand (COD) and total organic carbon (TOC) removal, respectively, were achieved after 120 min of EC at 9.09 mA cm(-2). For EO, two kinds of dimensionally stable anodes (DSA) electrodes (Ti/IrO₂-Ta₂O₅ and Ti/IrO₂-SnO₂-Sb₂O₅) were prepared by the Pechini method, obtaining homogeneous coatings with uniform composition and high roughness. The (·)OH formed at the DSA surface from H₂O oxidation were not detected by electron spin resonance. However, their indirect determination by means of H₂O₂ measurements revealed that Ti/IrO₂-SnO₂-Sb₂O₅ is able to produce partially physisorbed radicals. Since the characterization of the wastewater revealed the presence of indole derivatives, preliminary bulk electrolyses were done in ultrapure water containing 1 mM indole in sulfate and/or chloride media. The performance of EO with the Ti/IrO₂-Ta₂O₅ anode was evaluated from the TOC removal and the UV/Vis absorbance decay. The mineralization was very poor in 0.05 M Na₂SO₄, whereas it increased considerably at a greater Cl(-) content, meaning that the oxidation mediated by electrogenerated species such as Cl₂, HClO, and/or ClO(-) competes and even predominates over the (·)OH-mediated oxidation. The EO treatment of EC-pretreated dairy wastewater allowed obtaining a global 98 % TOC removal, decreasing from 1,062 to <30 mg L(-1).

Organics removal and protein recovery from wastewater discharged during the production of chondroitin sulfate

Bentonite, chitosan and polyaluminum chloride (PAC) were applied to treat wastewater discharged during the production of chondroitin sulfate and recover protein dissolved in the wastewater. The results showed that the combination of pH 9.00, 3-4 mL chitosan solution, 2 g of bentonite and 5 mL of 8% PAC solution per 100 mL of wastewater with a 4.0 h flocculation time were the optimal conditions for the recovery of protein and removal of total organic carbon (TOC) from wastewater. A pilot-scale test also was conducted, and 130 kg (dry weight) of sediment was obtained from 1.1 m(3) of discharged wastewater. This sediment contained abundant amino acids (proteins comprised 61% of the total sediment), after the recovery of protein, the dissolved TOC concentration in wastewater was decreased by approximately 80% and the residual wastewater could be readily disposed using a traditional activated sludge process.

Boat Pressure Washing Wastewater Treatment with Calcium Oxide and/or Ferric Chloride

The aim of this study was to investigate the efficiency of (1) chemical precipitation by calcium oxide, (2) coagulation/flocculation by ferric chloride (FC), and (3) the combination these two methods in reducing the toxicity of wastewater generated by boat pressure washing. All three methods gave satisfactory results in the removal of colour, turbidity, Cr, Fe, Cu, Zn, and Pb. The concentrations of heavy metals were lowered below national limits with 1 g of CaO, 2.54 mg of Fe3+ in the form of FeCl3x6H2O, and the combination of 0.25 g of CaO and 5.08 mg of Fe3+ per 50 mL of wastewater. Both CaO (1.50 g per 50 mL of wastewater) and FC proved efficient, but their combination yielded a significantly better performance: 99.41 %, 100.00 %, 97.87 %, 99.09 %, 99.90 %, 99.46 % and 98.33 % for colour, turbidity, Cr, Fe, Cu, Zn, and Pb respectively. For colour, Cr, Cu, Zn, and Pb removal efficiencies increased in the following order: FC<CaO<CaO+FC, while this order for turbidity and Fe was as follows: CaO<FC<CaO+FC. As expected, all three methods increased the concentration of total dissolved solids in the final effluent. Our results suggest that the combined treatment of marina wastewaters with calcium oxide followed by ferric chloride is efficient, cost-effective, and user-friendly.

Preliminary studies on growth and fresh weight of lettuce (Lactuca sativa) as affected by clay pot irrigation and spacing.

An experiment (Completely Randomized Design) was set up to determine the effects of Clay Pot Sub-surface Irrigation (CPSI) and spacing on the growth and fresh weight of lettuce (Lactuca sativa). The treatments were: CPSI with spacing; 15 x 15 cm, 20 x 20 cm and 30 x 30 cm. Control treatments were Watering Can Irrigation (WCI) with the same spacing as above. Treatments were replicated three times given a total of 18 experimental units. Eighteen large enamel basins of 50/20 cm (diameter/height) were filled with good topsoil and a clay pot buried neck deep in each of the basins. Seedlings were planted in all the eighteen basins. Five Hundred mL of wastewater was applied daily to plants in each container having either clay pot or watering can treatment. Plant height increased from 2.50 to 4.25 cm within 6 Weeks after Transplanting (WAT) under CPSI and only increased from 2.14 to 2.99 cm under WCI. The CPSI also supported better leave growth and fresh weight. The fresh weight of lettuce increased almost two fold under 15 x 15 cm spacing compared to 20 x 20 and 30 x 30 cm.

Synthesis and structure-activity study of quaternary ammonium functionalized β-cyclodextrin-carboxymethylcellulose polymers

Carboxymethylcellulose (CMC) and beta-cyclodextrin (beta-CD)-based polymers functionalized with two types of quaternary ammonium compounds (QACs), the alkaquat DMB-451 (N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride) (DMD-451) named polymer DMB-451, and FMB 1210-8 (a blend of 32 w% N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride and 48 w% of didecyldimethylammonium chloride) named polymer FMB 1210-8, were synthethized and characterized by Fourier transform infrared spectroscopy. The antimicrobial activities of these polymers against Eschericia coli were also evaluated at 25 degrees C in wastewater. The results have indicated that the polymer FMB 1210-8 possesses a high-affinity binding with bacterial cells that induces a rapid disinfection process. Moreover, in the same experimental conditions of disinfection (mixture of 1.0 g of polymer and 100 mL of wastewater), the polymer FMB 1210-8 has a higher antimicrobial efficiency (99.90%) than polymer DMB-451 (92.8%). This phenomenon might be associated to a stronger interaction with bacterial cells due to stronger binding affinity for E. coli cells and greater killing efficiency of the C10 alkyl chains QAC of polymer FMB 1210-8 to disrupt the bacterial cell membrane as compared to N-alkyl (50% C14, 40% C12, 10% C10) dimethylbenzylammonium chloride. Together, these results suggest that the polymer FMB 1210-8 could constitute a good disinfectant against Escherichia coli, which could be advantageously used in wastewater treatments due to the low toxicity of beta-CD and CMC, and moderated toxicity of FMB 1210-8 to human and environment.

Preparative separation of punicalin from waste water of hydrolysed pomegranate husk by macroporous resin and preparative high-performance liquid chromatography

The present study investigated a fast and cost-effective method for the preparation of punicalin from waste water of hydrolysed pomegranate husk by H-103 macroporous resin and preparative high-performance liquid chromatography (HPLC) using a mobile phase consisting of 10% (v/v) of methanol and 0.1% TFA in water for primary separation and a mobile phase consisting of 30% (v/v) of methanol and 0.1% TFA in water to remove gallic acid and other minor impurities. 120ml of waste water, which contained about 480mg punicalin, could produce 1147mg of punicalin-rich extract of 36.4% punicalin after separation by H-103 macroporous resin. 349mg of 97% punicalin could be obtained after purified by preparative HPLC. The recovery per litre of waste water was more than 70%. The product was assessed by analytical HPLC and characterised by MS and 1H NMR and 13C NMR. This method is practical for industrial applications and could provide a low-cost means to use a currently underutilized industrial by-product.

Application of electrochemically synthesized ferrate(VI) in the purification of wastewater from coal separation plant

The oxidative and coagulation efficiency of Na2FeO4 solution, electrochemically generated by trans-passive anodic oxidation of electrical steel in 10M NaOH solution, is confirmed in the process of purification of heavily contaminated wastewater from coal separation plant. The decontamination efficiency is evaluated comparing the values of selected contamination parameters obtained by chemical and biochemical analysis of plant effluent water and water obtained after decontamination with ferrate(VI) solution in relatively simple laboratory procedure. The sample of 450 ml of wastewater is treated in laboratory conditions with 100cm3 solution of 1 mg dm-3 Na2FeO4 in 10M NaOH. The chemical analysis of effluent water after treatment have shown almost 3 times lower permanganate index, about 3 times lower iron content, 1.45 times lower As3+ content, 7.35 times lower ammonia content. Turbidity and chemical oxygen demand (COD) is reduced for more than 5.77and 13.4 times, respectively. The suspended and colloid matter is eliminated from effluent water after treatment with ferrate(VI) solution. Also, biochemical exploration has confirmed high efficiency of ferrate(VI) in organics and microbial elimination showing 7.1 times lower 5-days bio-chemical oxygen demand (BOD5), and total elimination of aerobic and anaerobic bacteria from effluent water. According to standards on quality of industrial wastewater effluents, it may be concluded that ferrate(VI) treatment of wastewater almost completely eliminates excess of dangerous chemicals and pathogen bacteria, with the exemption of arsenic. Thus, ferrate(VI) shows capable performance in treatment of coal separation plant wastewater.

Analysis of cocaine and its principal metabolites in waste and surface water using solid-phase extraction and liquid chromatography–ion trap tandem mass spectrometry

A validated method based on solid-phase extraction (SPE) and liquid chromatography-ion trap tandem mass spectrometry (LC-MS/MS) is described for the determination of cocaine (COC) and its principal metabolites, benzoylecgonine (BE) and ecgonine methyl ester (EME), in waste and surface water. Several SPE adsorbents were investigated and the highest recoveries (95.7 +/- 5.5, 91.8 +/- 2.2 and 72.5 +/- 5.3% for COC, BE and EME, respectively) were obtained for OASIS HLB(R) cartridges (6 mL/500 mg) using 100 mL of waste water or 500 mL of surface water. Extracts were analysed by reversed-phase (RP) or hydrophilic interaction (HILIC) LC-MS/MS in positive ion mode with multiple reactions monitoring (MRM); the latter is the first reported application of the HILIC technique for drugs of abuse in water samples. Corresponding deuterated internal standards were used for quantification. The method limits of quantification (LOQs) for COC and BE were 4 and 2 ng L(-1), respectively, when RPLC was used and 1, 0.5 and 20 ng L(-1) for COC, BE and EME, respectively, with the HILIC setup. For COC and BE, the LOQs were below the concentrations measured in real water samples. Stability tests were conducted to establish the optimal conditions for sample storage (pH, temperature and time). The degradation of COC was minimal at -20 degrees C and pH = 2, but it was substantial at +20 degrees C and pH = 6. The validated method was applied to a set of waste and surface water samples collected in Belgium.

Heavy metal removal from industrial wastewater by clinoptilolite

Clinoptilolite- a natural zeolite has been investigated for the removal of heavy metals from the wastewaters. A pyrex-glass column of 30 mm diameter and 600 mm height was used. The column was filled with the conditioned clinoptilolite of 0.5–1 mm. In the first stage of the research, synthetic wastewater containing single cation 0.02 N and 0.04 N Cu and 0.02 N Fe and Zn solutions were passed through the column. Two liter of 0.02 N Cu and 750 ml of the 0.04 N Cu solution was treated with 100 percent removal efficiency. Clinoptilolite column was regenerated for the reuse when the removal efficiency decreased. The cation exchange capacities were calculated as 1.0663 and 1.5342 meq/g clinoptilolite for 0.02 N and 0.04 N Cu solutions, respectively. In the second stage of this research, the same procedure was repeated with the actual wastewater samples of the equalization and the neutralization tanks of the Telka-Rabak Electrolytic Copper Industry. A volume of 1811 ml of the wastewater of the equalization tank and 180 ml of the neutralization tank wastewater, which had high concentrations of Ni, Zn, Cu and Fe, was treated with 100 percent efficiency. The cation exchange capacities of clinoptilolite for the wastewater of the equalization and the neutralization tanks for Cu were 0.4483 and 0.4274, respectively. It was observed that only one third of the single copper ion solutions were obtained with the actual wastewater having competing ions such as Zn, Fe and Ni. The experimental results also indicate that the clinoptilolite is an effective cation exchanger for the removal of the metals from the wastewater and the removal efficiency is higher when there is not ant competing ions.

Determination of acidic pharmaceutical products and carbamazepine in roughly primary-treated wastewater by solid-phase extraction and gas chromatography–tandem mass spectrometry

A gas chromatography–tandem mass spectrometry (GC–MS/MS) method has been developed for the determination of selected pharmaceutical residues (carbamazepine, salicylic acid, clofibric acid, ibuprofen, 2-hydroxy-ibuprofen, fenoprofen, naproxen, ketoprofen, diclofenac, and triclosan) in sewage influent and roughly primary-treated effluent. The method involved solid-phase extraction (SPE) with polymeric sorbents, and two SPE cartridges were compared for the extraction and elution of the targeted compounds in complex matrices. A successful chemical derivatization of carbamazepine and acidic compounds using N,O-bis(trimethylsilyl) trifluoroacetamide +10% trimethylchlorosilane is also described. The quantification limits of the analytical procedure ranged from 30 to 60 ng L−1 for 500 mL of wastewater. The best recovery rates (72–102%) in spiked effluent samples were obtained with Phenomenex Strata-X™ cartridges. Detection limits (S/N = 3) were estimated at between 1 and 18 ng L−1. The reported GC–MS/MS method significantly reduces the strong matrix effects encountered with more expensive LC-MS/MS techniques. Application of the developed method showed that most selected analytes were detected at concentrations ranging from low µg L−1 to trace level ng L−1 in Montreal's wastewater treatment plant effluent and influent, as well as in the receiving waters at more than 8 km downstream of the effluent outfall. The rugged alternative analytical method is suitable for the simultaneous analysis of carbamazepine and pharmaceutical acidic residues in wastewater samples from influents and effluents that have undergone rough primary treatment.

Evaluating the fish safety level of river water and wastewater with a larval medaka assay

A larval medaka ( Oryzias latipes) assay was proposed to evaluate the fish safety level of river waters and wastewaters. Organic toxicants were 10–100 times concentrated with adsorption cartridges from 4 l of river water or 1–10 times concentrated from 400 ml of wastewater. Toxicity of these concentrated solutions was determined by exposing 48–72 h post-hatch age larvae for 48 h. The method effectively revealed a variation of the median lethal concentration ratio (LCR 50) from 13 to >100 in 125 river water samples, and from <1 to >10 in five typical wastewater samples. Ayase River, which takes water mostly from agricultural or household discharge, showed significantly ( P < 0.001) lower LCR 50 than Sagami River that takes natural water as the source. Safety Levels in both Sagami River and Ayase River were influenced by the irrigation activity, LCR 50 at some sites showing a seasonal-specific decrease in winter. Pollution from pulp and paper industries contributed to the low LCR 50 in several tributaries of Ayase River. Required little manpower in sampling, pretreatment and testing, the proposed larval medaka assay was proved as an efficient tool for screening those high risk sites for priority management.

Penurunan COD (Chemical Oxygen Demand) dalam Limbah Cair Laboratorium Menggunakan Filter Karbon Aktif Arang Tempurung Kelapa

This research use activated carbon from coconut shell as a media to removal of COD in laboratory wastewater. The research is done at UII laboratory with use batch and continuous reactor. At the batch reactor use variation of pH : 7, 8, 9,10 and initial concentration of COD 85,8 mg/L, 81,3 mg/L, 61,2 mg/L, 53,8 mg/L. Doses of activated carbon is 1, 2, 3, 4 grams each 200 ml of wastewater. Rapid mixing at the batch reactor is 150 rpm as long as 2 hours. For continuous reactor is make with series, that is two reactor column. In this system is used wastewater with initial concentration of COD 97,68 mg/L and pH 8. The sampling is taken each one hours after reactor have operation. The result of sample test show that activated carbon from coconut shell be able to removal of COD in the laboratory wastewater. The biggest efficiency of removal is 68 % at the activated carbon doses 4 mg and pH 8. Models of sorption with isotherm Freundlich is gotten equation x/m = 0,0009*C0,3281. On the continuous reactor, the biggest efficiency of removal are 61,99 % at the first column and 75 % at the second column. Based on the result of this research, so that activated carbon form coconut shell possible to applied as a alternative treatment to laboratory wastewater, specially wastewater on the UII laboratory. keyword : Activated carbon, Laboratory wastewater, Removal of COD

Appropriate preservation of dairy wastewater samples for environmental analysis.

Thousands of gallons of water are used in dairies to wash cows before milking and for cleaning equipment. The wastewater generated contains elevated levels of organic matter and pollutants, including nitrogen that once converted, may contaminate groundwater with nitrate. This study was conducted to determine the amount of sulfuric acid needed to preserve wastewater samples from a New Mexico dairy in the southwestern U.S. Titrations of wastewater from a local dairy using full strength (18 M) sulfuric acid were performed to determine the amount of acid needed to bring the pH of the sample to below two, the recommended pH for sample preservation. An average of 0.33 mL of acid was required for every 100 mL of wastewater. Due to sample variability, we recommend that 0.4 mL sulfuric acid be added for every 100 mL dairy wastewater sample to ensure adequate acidification. This quantity is twice the amount currently recommended in U.S. Environmental Protection Agency guidelines.

Removal of metal ions by modified Pinus radiata bark and tannins from water solutions

Pinus radiata bark and tannins, chemically modified with an acidified formaldehyde solution were used for removing metal ions from aqueous solutions and copper mine acidic residual waters. The adsorption ability to different metal ions [V(V), Re(VII), Mo(VI), Ge(IV), As(V), Cd(II), Hg(II), Al(III), Pb(II), Fe(II), Fe(III), Cu(II)] and the factors affecting their removal from solutions were investigated. Effect of pH on the adsorption, desorption, maximum adsorption capacity of the adsorbents, and selectivity experiments with metal ion solutions and waste waters from copper mine were carried out. The adsorbents considerably varied in the adsorption ability to each metal ion. The adsorption depends largely upon the pH of the solution. Modified tannins showed lower adsorption values than the modified bark. For the same adsorbent, the maximum capacity at pH 3 for the different ions were very different, ranging for modified bark from 6.8 meqg −1 for V to 0.93 meqg −1 for Hg. Waste waters were extracted with modified bark as adsorbent and at pH 2. The ions Cu(II) (35.2 mgL −1), Fe(III) (198 mgL −1), Al(III) (83.5 mgL −1) and Cd(II) (0.15 mgL −1) were removed in 15.6%, 46.9%, 83.7% and 3.3%, respectively, by using 1 g of adsorbent/10 mL of waste water. In general, a continuous adsorption on a packed column gave higher adsorbed values than those observed in the batchwise experiment.

Treatment of Wastewater with High Inorganic Salts Content

The study deals with the waste disposal of an aqueous solution with a high salt content (about 5% sodium sulfate) and an organic fraction consisting primarily of naphthalenesulfonic acids. First, a process based on crystallization for the removal of sodium sulfate from the wastewater was developed, leading to a recovery of about 70% of the sodium sulfate. The wastewater with the residual salts content was fed to a batch mesophilic anaerobic digestion process. The acclimatization of a methanogenic consortium to different mixtures of the desalted wastewater and a growth substrate was studied. Complete acclimation of the biomass to the solution was observed over a broad range of wastewater amount in a growth medium (from 3.5 to 224 mL of wastewater per liter of feeding solution). After a suitable acclimation period of time the biomass was able to digest the pure wastewater up to an amount of 57.1 mL per liter of the feeding solution, obtaining total organic carbon (TOC) (mg/LC) removal rates of 0.04 kg TOC/k...

Determination of linear alkylbenzene sulfonates and their polar carboxylic degradation products in sewage treatment plants by automated solid-phase extraction followed by capillary electrophoresis-mass spectrometry.

Linear alkylbenzene sulfonates (LAS) were determined by solid-phase extraction (SPE), followed by capillary electrophoresis and mass spectrometry detection (CE-MS). The linear range of the proposed method varied from 33 to 316 and from 215 to 2057 micrograms L-1, depending on the compound, with limits of detection ranging from 4.4 to 23 micrograms L-1 when 200 ml of wastewater were preconcentrated. The analysis and confirmation of the polar carboxylic metabolites of LAS, the sulfophenyl carboxylic acids (SPC) was also achieved, and their presence was detected in both, influent and effluents of the sewage treatment plant (STP). [M - H]- ions were used for CE-MS confirmation and quantification. CE-MS diagnostic ions were the same ones used in LC-electrospray (ESI)-MS and corresponded to m/z 297, 311, 325 and 339 for C10LAS, C11LAS, C12LAS and C13LAS, respectively. For SPC identification, diagnostic ions corresponded to m/z 215 to 369 (with 14 mass unit steps) for C2 to C13SPC, respectively. LAS were determined in wastewater samples of the influent and effluent of three sewage treatment plants (STP), two of them using biological treatment with secondary settlement and receiving mainly domestic wastewater whereas one of the plants was operated with physiochemical treatment and received mainly industrial wastewater. The concentration levels of total LAS varied from 1000 to 1900 micrograms L-1 in the influents of STP, whereas in the effluents the concentrations varied from 125 to 360 micrograms L-1.

Strategies for the sustainable management of industrial wastewater. Determination of the chemical dynamics of a cascade series of five newly constructed ponds

The Portland Aluminium smelter, located near the town of Portland, Australia, currently discharges over 715 ML of wastewater into the ocean each year. As an alternative to ocean discharge, Portland Aluminum has constructed a number of trial evaporation ponds to receive this wastewater. These ponds must not only be efficient evaporative pans, they must not pollute nearby wetlands, and also be aesthetically pleasing. Hence, water quality is a major issue. In this study, a comparison was made between the concentrations of fluoride (F), sulphate (SO42−), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), and chloride (Cl−) ions in the ponds. Our results show that there was a correlated increase in fluoride, sodium, potassium, chloride, magnesium and sulphate concentrations in April and May 1998 in the constructed ponds, followed by a significant reduction in ion concentration by July 1998 (p < 0.001). Calcium ion was the only ionic species to not behave in this manner. Statistically there was no significant change in calcium concentration over time in the constructed ponds (p > 0.05).

Improvements in the determination of organophosphorus pesticides in ground- and wastewater samples from interlaboratory studies by automated on-line liquid-solid extraction followed by liquid chromatography-diode array detection

On-line liquid-solid extraction coupled to liquid chromatography and diode array detection (LSE-LC-DAD) was validated by participating in interlaboratory calibration studies organized by Aquacheck (Medmenham, UK). The quantitation of 11 organophosphorus pesticides ground- and wastewater samples at levels varying from 30 to 600 ng/l respectively was carried out. The solution containing the organophosphorus pesticides and the water sample was provided by Aquacheck. Between 90 and 150 ml of wastewater and ground respectively were percolated through the Prospekt C 18 precolumns (Spark Holland). The average error in comparison to the certified values from Aquacheck varied from 4 to 65%. The main problems encountered in the determination of these pesticides were the low UV absorbance of dichlorvos, mevinphos and malathion, the early breakthrough of dichlorvos and mevinphos and matrix interferences, specially abundant in the wastewater samples. In this type of water samples, the spiked level was one order of magnitude higher than in groundwater, but the error percentage was higher due to the matrix. One of the main advantages of this technique is that it permits the identification of two isomers of mevinphos, contrary to the rest of the participants who only reported trans-mevinphos. Moreover, by percolating 150 ml of water, limits of detection (LODs) below 0.1 μg/l are attained. The system behaved linearly over a concentration range of 0.4 to 5 ng/ml with 150 ml of water preconcentrated.

Salmonella in a wastewater-Aquaculture system

Levels of Salmonella (MPN) were measured in wastewater and silver carp Hypothalmichthys molitrix cultured in the wastewater. Sera of the cultured fish were examined for antibodies to Salmonella. Salmonella were isolated from 21 of 90 water samples and 2 of 63 fish samples. Highest levels were 4·3 cells per 100 ml of wastewater and 5·5 cells per g of fish intestine. No agglutinating antibodies against Salmonella were evident in the serum samples tested. Silver carp and channel catfish received an inoculum of Salmonella into the anterior intestine. At 35 days post-inoculation, all fish were serologically negative.

Fluorescent-antibody method useful for detecting viable but nonculturable Salmonella spp. in chlorinated wastewater

An indirect fluorescent-antibody (IFA) technique, which employed adsorbed Behring polyvalent I O antiserum, was used to detect Salmonella spp. in environmental water systems. The IFA method used in this study detected 95% of Salmonella serotypes encountered in human infections in France, with a sensitivity threshold of 7.5 x 10(3) bacteria per ml of wastewater. Specificity was assessed by testing IFA against Salmonella-free seawater and a variety of bacteria other than Salmonella spp. When used to examine raw and chlorinated wastewater over a 2-month period, the IFA method was successful in detecting Salmonella spp. in all 12 of the samples examined, with total numbers determined to be 4.5 x 10(5) to 3.3 x 10(7) salmonellae per 100 ml. In comparison, for the same samples, enumeration by culture, using the most-probable-number technique, was effective in detecting Salmonella spp. in only four of eight raw-water samples and one of four chlorinated water samples tested. Three samples were further tested by using the direct viable count procedure combined with IFA and results showed that 5 to 31.5% of the Salmonella spp. enumerated by this method in chlorinated water were substrate responsive.